Peter of Spain

Peter of Spain, the Author of the Summulae

The Author of the Summulae

Until recently, there was quite general agreement among scholars concerning the identity of the author of one of the most successful academic books ever, the Summulae Dialecticales. According to the commonly accepted opinion, the author was Petrus Iuliani, who became pope John XXI, a man of science almost to the point of neglecting his papal duties in favor of his research, whose papacy came to an abrupt end after only eight months, when the ceiling of his newly-built private study in the Viterbo palace collapsed upon him in 1277. The so-called Byzantine thesis concerning the authorship of the Summulae, according to which it is a Latin translation of an original Greek work by the 11th-century Byzantine scholar, Michael Psellos, by now is a mere curiosity of intellectual history. Study of the sources has definitively shown that the Greek work mistakenly attributed to Psellos is in fact a Greek translation of the Latin work, prepared by Gennadios Scholarios in the 15th century. (de Rijk, 1972, pp. LXI-LXVIII.) However, careful study of the historical evidence by Professor Angel d’Ors (d’Ors, 1997.) successfully revived another tradition concerning the authorship of the Summulae, often referred to as the Dominican thesis. Indeed, Professor d’Ors’s study has established that the identification of the author of the Summulae with John XXI is probably a relatively late tradition, and the evidence supporting the Dominican thesis, according to which the author was a Dominican friar, is much stronger. However, Professor d’Ors found the evidence insufficient for a definitive positive identification of the actual person. Some sources refer to the author by the name of Petrus Alfonsi, others as Petrus Ferrandus, but there may be other candidates as well. Therefore, until the issue of authentic authorship is settled, the name ‘Peter of Spain’ (and its equivalents, Petrus Hispanus, etc.) should be used simply as an abbreviation of the definite description ‘the author of the Summulae’. In any case, this is the policy this article will follow.

Peter of Spain (whoever he was) was justifiably famous for authoring the Summulae. The work was on the core curricula of many universities for centuries, until it became one of the prime targets of humanist mockery of “scholastic barbarisms”, and was gradually eliminated from university curricula with the rest of the scholastic output. (Ashworth, 1974, pp. 9-20.) But Peter was also famous for authoring another important logical work, under the title Syncategoreumata, dealing with the properties of syncategorematic terms, i.e., various types of logical connectives.

The rest of this article will be devoted to a doctrinal analysis of the Summulae, focusing on its original contribution to the characteristically medieval doctrine of the properties of terms, and – also drawing on the doctrine of the Syncategoreumata – pointing out its significance concerning the problem of universals and philosophical realism in general.

The Summulae and the Realism of Peter of Spain

The Summulae is a systematic logical work consisting of twelve tracts, which fall into two main groups: (A) those providing the standard Aristotelian-Boethian teachings of the so-called logica antiqua (comprising the materials of logica vetus and logica nova), and (B) those providing the doctrine of the so-called logica modernorum, the original medieval contribution to logical theory. (Cf. De Rijk, 1962, pp. 14-17.)

The tracts according to this grouping are the following:

(A)

1. On introductory matters (De introductionibus), Tract I.
2. On predicables (De predicabilibus), Tract II.
3. On categories (De predicamentis), Tract, III.
4. On syllogisms (De syllogismis), Tract IV.
5. On topics (De locis), Tract V.
6. On fallacies (De fallaciis), Tract VII.

(B)

1. On suppositions (De suppositionibus), Tract VI.
2. On relatives (De relativis), Tract VIII.
3. On ampliations (De ampliationibus), Tract IX.
4. On appellations (De apppellationibus), Tract X.
5. On restrictions (De restrictionibus), Tract XI.
6. On distributions (De distributionibus), Tract XII.

The tracts belonging to the logica antiquagroup provide a simple, elementary exposition of Aristotelian-Boethian logic, as it was adopted in the 12th-century logical literature. (cf. De Rijk, 1972, pp. LXXXVIII-XCV.)

It is the tracts of logica modernorum that contain Peter’s contribution to the characteristically medieval theory of the properties of terms, analyzing and classifying the semantic functions of terms. The tract on suppositions first defines the primary semantic property of terms, which has to precede their supposition, namely, signification.

According to Peter, signification is the conventional representation of some thing by an utterance. Therefore, only those terms have signification that signify some thing, i.e., categorematic terms (namely, such terms that can meaningfully be the subject or predicate of propositions, while not taken to stand for themselves). Indeed, Peter goes on to argue that since every thing is either particular or universal, and syncategorematic terms, such as ‘every’, ‘some’, etc., do not signify either a universal or a particular thing, they do not signify some thing, and so they do not have signification in this strict sense. Nevertheless, as we shall see, this does not mean that these terms are absolutely meaningless. In fact, Peter will argue that although such terms do not signify things, they do signify certain modes of the things signified by categorematic terms. For now, however, we should just note Peter’s unabashed talk about universal things in this argument.

Peter divides signification into the signification of substantive things, performed by substantive nouns, and the signification of adjective things, performed by adjective nouns or verbs. Peter insists that this distinction does not characterize modes of signification, but modes of things.

Whatever these things and their modes are, Peter states that it is on account of the difference between these two types of signification that we have to distinguish between supposition and copulation.

Supposition is the taking of a substantive term for something, whereas copulation is the taking of an adjective term for something, i.e., its referring to something. This is why signification is prior to supposition. Since only a term can refer, supposition (i.e., reference) can only belong to a term, that is, an utterance that already has signification.

Peter first divides supposition into discrete and common supposition. Discrete supposition belongs to discrete terms, i.e., terms that on account of their signification can apply only to one thing, such as proper nouns, or common terms determined by a demonstrative pronoun and an act of pointing. Common supposition belongs to common terms, i.e., terms that on account of their signification can apply to several things.

Common supposition is further divided into natural and accidental supposition. Natural supposition is the taking of a common term for all those things that fall under it, be they past, present, or future. Although Peter does not say much about this type of supposition, its significance is clear in natural science, where we want to make universal claims of natural phenomena regardless of whether they are actual at the time of making the claim or not. For example, ‘Every lunar eclipse is the interposition of the earth between the sun and the moon’ should be true, even when there is no lunar eclipse. Accidental supposition is the taking of a term in a proposition for something, as determined by the propositional context.

Accidental supposition is further divided into simple and personal supposition. (In medieval logic it was also common to distinguish material supposition, when a term stands for itself, as in ‘Man is a noun’, but Peter omits this type of supposition from his considerations.)

According to Peter, in simple supposition a common term refers to the universal thing it signifies. For example, in the proposition ‘Man is a species’ the term ‘man’ stands for what it signifies, namely, man in general, and not any particular man, since obviously no particular man is a species. Furthermore, the predicate terms of universal affirmative propositions also have simple supposition. For example, in ‘Every man is an animal’, the term ‘animal’ cannot be taken to stand for any particular animal, for obviously no particular animal is every man.

Personal supposition is defined by Peter as the taking of a common term for its inferiors. It is divided into determinate and confused, the latter of which is further subdivided into mobile and immobile supposition. Determinate supposition is had, for example, by the subjects of particular propositions, such as ‘Some man is running’. It is called determinate, for although the term ‘man’ stands in it for all men, it is verified for just any one of them (i.e., it is true, if this man is running, or that man is running, etc.). Confused supposition, according to Peter’s definition, is the taking of a common term for many things, with the mediation of a universal sign. For example, the subject term of ‘Every man is an animal’ has confused, mobile, and distributive, supposition, for the term is obviously held for all men, and, contrary to determinate supposition, the proposition is true only if the predicate is verified for all of them (i.e., it is true, if this man is an animal and that man is an animal, etc.). Peter goes on to distinguish this type of confused supposition, which he calls confused by the necessity of the sign, from another type, which he calls confused by the necessity of the thing.

That the subject term of ‘Every man is an animal’ is distributed for all men because of the universal sign ‘every’ is clear. But, Peter argues further, since each man has his own essence, and his own animality, the copula ‘is’ and the predicate term ‘animal’ should also be taken to stand for all those essences and all those animals, not by the necessity of the sign, but by the necessity of the thing.

The term confused by the necessity of the sign is taken distributively, for it is taken to stand for all men, but it has confused and mobile supposition, because one can “descend” to any of its inferiors by a valid inference, such as this: ‘Every man is an animal; therefore, Plato is an animal’. By contrast, the term confused by the necessity of the thing has confused, but immobile supposition, for under this term no such descent is possible: the inference ‘Every man is an animal; therefore, every man is this animal’ is not valid.

However, in his discussion of simple supposition it was precisely this property of the predicate term of this sentence that allowed Peter to conclude that this term had simple supposition. In general, Peter’s criterion there to detect whether a term had simple supposition seemed to be whether the term could be taken to stand for any one of its particulars, preserving the truth of the proposition. So which kind of supposition applies here?

Peter first addresses this problem by pointing out that attributing both simple and immobile personal supposition to the same term is not inconsistent. For it has simple supposition insofar as it stands for the nature of the genus predicated of its species, but it has confused supposition insofar as the nature of the genus is multiplied in the supposita of the species.

But Peter is not satisfied with this solution, for he finds it simply impossible that a term should have confused personal supposition in the predicate position. He argues as follows. In ‘Every man is an animal’ a genus is predicated of one of its species. But the nature of the genus multiplied in the supposita of the species is not a genus. Therefore, it is not the nature of the genus multiplied in the supposita of the species that is predicated here. But the predicate of this sentence stands for what is predicated, which is not the nature of the genus multiplied in the supposita of the species, whence it cannot have confused supposition which would require this multiplication.

Peter’s consequent rejection of the aforementioned distinction between the two types of confusion (which he found in one of his sources, cf. de Rijk, 1972, p. LXXI.) gives us a clearer insight into Peter’s semantic conception. Here he states that although from the point of view of logic the nature signified by ‘man’ in its supposita is one, in the nature of things each man has his own humanity, and these humanities are distinct on account of the matter they inform. Likewise, the nature signified by the term ‘animal’ in individual humans is one from the point of view of logic (secundum viam logice), but is multiplied in these individuals in the nature of things (secundum viam nature). So, the multiplication of animalities has nothing to do with the semantic function of the predicate of ‘Every man is an animal’; indeed, we find the same multiplication of animalities even when we consider ‘Every man is white’ or ‘Every man is black’.

So Peter’s apparently naïvely realist talk about universal things need not be taken at face value. It is only the proper way of talking for the logician, who is discussing things insofar as they are conceived by us, and consequently signified by our terms. But since we are able to conceive of singular things in a universal manner, by abstracting from their differences, and consequently we are able to signify them in the same way, the logician is entitled to talk about what our common terms signify as a universal thing, while keeping in mind that the thing in question is not a thing of nature, but something universally conceived and signified. (Cf. also Peter of Spain, 1992, pp. 46-49 and 104-105.)

So, to summarize Peter’s conception by means of an example, the term ‘man’ signifies human nature in general, and this is what it stands for when it has simple supposition, as in ‘Man is a species’ or ‘Every philosopher is a man’. But the same term stands for the individuals having this nature (each one its own), when the term has personal supposition, whether determinate, as in ‘A man is an animal’ or confused, mobile and distributive, as in ‘Every man is an animal’. However, Peter rejects the suggestion that the predicate term of this sentence, besides having simple supposition would also have personal (confused and immobile) supposition, not because he thinks these two kinds of supposition would be incompatible, but because he argues that this predicate simply does not have the latter semantic function.

All this squarely places Peter of Spain in the moderate realist position concerning the problem of universals. However, there is more to Peter’s realism. If in a very general sense we take a realist to be someone who is willing to allow a one-to-one mapping of linguistic categories to ontological categories (at least, in most, and significant cases), as opposed to a nominalist who would reduce his ontological commitment by arguing for many-to-one mappings, then Peter will appear to be a realist even in this general sense. To be sure, his realism is certainly mitigated by his distinction between what one can talk about secundum viam logice and what there really is secundum viam nature. Nevertheless, the way he talks about substantive and adjective things, and especially about the signification of syncategorematic terms is revealing. The things he is talking about may not be things of nature pure and simple, but things-as-conceived-and-signified. But then, as far as Peter’s semantics is concerned, there might be (almost) just as many such “quasi-things” as there are different ways of signifying the things of nature (disregarding, e.g., synonymies).

This is quite clear not only in Peter’s distinction between adjective and substantive things referred to above (which after all reflects a genuine real distinction between substances and accidents), but especially in his treatment of the signification of syncategorematic terms and of propositions. As far as the latter are concerned, he does not hesitate to talk about what is signified by a proposition, and referred to by the corresponding sentential nominalization, as a thing, which may have its own accidents. (Cf. Peter of Spain, 1972, p. 195.) As for syncategorematic terms, Peter both in the last tract of the Summulae and in the Syncategoreumata insists that although syncategorematic terms do not signify subjectible and predicable things, which are signified by categorematic terms, nevertheless, they do signify certain modes of these things. To be sure, he adds, these modes do not belong to these things as they are in themselves, but insofar as they are subjectible or predicable, which is why they need not stick with their things in syllogisms in different propositions. For example, consider

Every white man is running
Socrates is a white man
------
Socrates is running

In this syllogism, the disposition ‘white’ of the subject ‘man’ belongs to the thing in itself, so it has to be repeated in the other premise in order to get a valid inference. However, the further disposition ‘every’ need not be repeated (i.e., we do not have to assume ‘Socrates is every white man’ as the second premise) in order to obtain a valid inference. In Peter’s view, this is because ‘every’ signifies a disposition that determines the subject in relation to the predicate, for it signifies that the predicate applies to all supposita of the subject.

The remaining tracts of the Summulae deal with the supposition of relative pronouns (tr. VIII), the modifications of supposition in various propositional contexts (tr. IX, XI, XII), and supposition for the actually existing supposita of a term, distinguished by the name of appellation (tr. X.), in marked contrast with John Buridan’s later interpretation of appellation.